This invention relates to a hydraulic connecting device for interconnecting a hydraulic multi-line hose and a hydraulic coupling device, the multi-line hose having a plurality of flexible hydraulic conduits housed within a protective sheath, and the coupling device having a plurality of plug pins held within a casing by a retainer. The invention is particularly useful in the hydraulic distribution systems used in underground mine workings, particularly for hydraulic advanceable mine roof support assemblies and other hydraulic appliances. Such hydraulic systems usually use an oil/water emulsion as the hydraulic fluid, but other fluids including air can also be used.
Systems are known in which numerous hydraulic conduits are bunched together to form multi-line hoses. Multi-line hoses are interconnected by means of pairs of complementary hydraulic coupling devices. One coupling device of each pair houses a plurality of male plug pins which are attached to the conduits of one multi-line hose; and the other coupling device of that pair houses a plurality of female plug pins (or sockets) which are attached to the conduits of a second multi-line hose. The female plug pins mate with the male plug pins when the two coupling devices are attached (usually by the interengagement of complementary screw threads on their casings), thereby connecting the two multi-line hoses. The plug pins are, in each case, held within radial slots or circular apertures provided in a retainer mounted in the casing of the coupling device. (See DE-AS No. 2,059 576 and DE-GM No. 79 03535)
With systems of this type, the protective sheath of a given multi-line hose is attached to the casing of its coupling device in such a manner as to resist tensile forces, but so as to be rotatable relative thereto.
The aim of the present invention is to provide an improved connecting device for interconnecting a multi-line hose and a coupling device, which connecting device can resist tensile forces whilst permitting relative rotation between the coupling device and the hose, which can be fitted in a simplified manner, which is as compact as possible, and whose cost of manufacture is as low as possible.